Network Congestion Analysis

ABSTRACT

A network monitoring and network congestion analysis can be performed based on a comparison of data packets at multiple different network nodes installed at different locations on a communication path. A downstream network node may be installed at a user location while an upstream network may be installed at an access router further up the network. A network congestion analyzer may receive data packet information including timestamps from both network nodes, and may compare the data packet information to group the data packets into application flows and match the corresponding packets from the different network nodes. Based on the data packet matching, the network congestion analyzer may calculate packet loss, packet delay, packet delay variation, and perform other network congestion analysis techniques for the application flows corresponding to a user&#39;s various devices and the applications executing on those devices.

RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 13/041,927, entitled, “Network Congestion Analysis,” filed Mar.7, 2011, the contents of which are incorporated herein by reference intheir entirety for all purposes.

BACKGROUND

Modern network environments often include several different computingdevices at an end user's location connected to an external network overa single communication path. For example, a user's home or office mayhave multiple computers, televisions and set-top boxes, mobile devices,gaming consoles, and other communication devices connected to aninterface such as a gateway and/or modem, so that the devices competefor network bandwidth. Users typically purchase a finite amount ofupstream and downstream bandwidth from a network provider, and theseamounts may be enforced by the user's gateway or other networkcomponent. When the combined network usage of the user's devices exceedsthe available bandwidth, the user may experience delays and performancedegradation on one or more of the devices. However, the user may have noway of determining which network devices are taking up significantamounts of bandwidth at that particular time. Moreover, the user mightnot even be sure that the performance problems are related to the user'sbandwidth limitations. For example, the user may suspect that theperformance problems of the devices are caused by congestion furtherupstream on the network (e.g., at a shared access router, centraloffice, etc.), or by problems within the devices themselves (e.g.,hardware malfunctions or software errors).

Thus, although a user may attempt to remedy performance problems,neither the user nor the provider may know the precise cause or locationof the performance problems. One attempted solution is for the user topurchase additional bandwidth from the network provider. However, thissolution is entirely speculative and will not correct the user's problemif the cause of the problem is within the devices themselves, or if theproblem is further upstream on the network. Thus, the user will bereluctant to make the additional purchase without greater assurance thatthe additional bandwidth will correct the problems with the user'sdevices. Additionally, if the performance problems are caused byexcessive bandwidth usage of one of the user's devices, then simplypurchasing more bandwidth will not allow the user to identify theoffending device or reconfigure the device to correct the problem.

Accordingly, there remains a need for network monitoring and networkcongestion analysis techniques that support additional abilities tocoordinate growing numbers of user devices and applications that competefor finite network bandwidth.

SUMMARY

Some aspects of this disclosure relate to methods and systems fornetwork monitoring and network congestion analysis based on a comparisonof data packets at multiple different network nodes installed atdifferent locations on a network path.

For example, one or more intermediary network nodes may be configured toreceive and capture data packets from one or more transmitting nodes,and transmit corresponding data packet information to a networkcongestion analyzer. A first intermediary network node may be installedon a network path at a user location (e.g., a customer's home orbusiness), while a second intermediary network node may be installedfarther upstream on the network path, for example, at an access routeror other network component. The intermediary network nodes may beconfigured to copy and store identifying characteristics of the datapackets transmitted through the network nodes, including timestampsassociated with the data packets. The intermediary network nodes mayreceive a time signal from an external time source in order tosynchronize the timestamps created for their respective data packets.After receiving and processing the data packets, the intermediarynetwork nodes may transmit the data packets to their intendeddestination nodes, and may also transmit the data packet information,including the timestamp data, to the network congestion analyzer.

A network congestion analyzer may be configured to receive data packetinformation from a plurality of intermediary network nodes, and mayidentify individual data packets within the data packet information andmay group those data packets into application flows corresponding tospecific devices, software applications, and/or connections from a userlocation. Additionally, the network congestion analyzer may matchindividual data packets received from a first network node (e.g., adownstream network node) with data packets received from a secondnetwork node (e.g., an upstream network node), and may compare thetimestamps associated with the corresponding data packets to determinenetwork statistics such as packet loss, packet delay, and packet delayvariance within the application flows on the network path. The networkcongestion analyzer may be configured to transmit control instructionsto the plurality of intermediary network nodes, for example, to instructthe network nodes to begin capturing data packets, stop capturing datapackets, compress and/or filter the data packets based on variousproperties, and transmit the captured data packets back to the networkcongestion analyzer.

Data packet matching techniques for different network protocols may beused. For example, a network congestion analyzer may determine that areceived data packet is either a Transmission Control Protocol (TCP) orReal-time Transport Protocol (RTP) data packet, and may use thecharacteristics of the data packet (e.g., source address and port,destination address and port, etc.) along with the TCP or RTP sequencenumber to identify the data packet and match the packet with acorresponding packet from another intermediary network node. In otherexamples, the network congestion analyzer may determine that a receiveddata packet is a User Datagram Protocol (UDP) data packet, and may usesimilar data packet characteristics, along with a hash signaturegenerated based on the UDP packet payload, to identify and match thedata packet.

The preceding presents a simplified summary in order to provide a basicunderstanding of some aspects of the disclosure. The summary is not anextensive overview of the disclosure. It is neither intended to identifykey or critical elements of the disclosure nor to delineate the scope ofthe disclosure. The summary merely presents some concepts of thedisclosure in a simplified form as a prelude to the description below.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is illustrated by way of example and not limitedin the accompanying figures in which like reference numerals indicatesimilar elements and in which:

FIGS. 1 and 2 illustrate an example information distribution network onwhich certain features described herein may be implemented.

FIG. 3 illustrates an example hardware platform on which certainfeatures described herein may be implemented.

FIGS. 4A-4C are example flow diagrams illustrating methods for receivingdata and performing a network congestion analysis in accordance withsome aspects of the disclosure.

FIG. 5 is an example graph showing bandwidth usage in accordance withsome aspects of the disclosure.

FIG. 6 is an example table showing network data statistics in accordancewith some aspects of the disclosure.

FIG. 7 is example flow diagram illustrating a method for receiving datapackets and transmitting data packet information in accordance with someaspects of the disclosure.

DETAILED DESCRIPTION

In the following description of various illustrative embodiments,reference is made to the accompanying drawings, which form a parthereof, and in which is shown, by way of illustration, variousembodiments in which aspects of the disclosure may be practiced. It isto be understood that other embodiments may be utilized, and structuraland functional modifications may be made, without departing from thescope of the present disclosure.

FIG. 1 illustrates an example information/content distribution and/orcommunication network 100 on which many of the various featuresdescribed herein may be implemented. Network 100 may be any type ofinformation distribution network, such as satellite, telephone,cellular, wireless, etc. One example may be an optical fiber network, acoaxial cable network or a hybrid fiber/coax (HFC) distribution network.Such networks 100 use a series of interconnected communication lines 101(e.g., coaxial cables, optical fibers, wireless, etc.) to connectmultiple user locations 102 (e.g., businesses, homes, offices, consumerdwellings, etc.) to a central office or headend 103. The central office103 may transmit downstream information signals onto the lines 101, andeach user locations (e.g., home 102) may have a receiver used to receiveand process those signals.

There may be one line 101 originating from the central office 103, andit may be split a number of times to distribute the signal to varioushomes 102 in the vicinity (which may be many miles) of the centraloffice 103. The lines 101 may include components not illustrated, suchas splitters, filters, amplifiers, etc. to help convey the signalclearly, but in general each split introduces a bit of signaldegradation. Portions of the lines 101 may also be implemented withfiber-optic cable, while other portions may be implemented with coaxialcable, other lines, or wireless communication paths. By running fiberoptic cable along some portions, for example, signal degradation inthose portions may be significantly minimized, allowing a single centraloffice 103 to reach even farther with its network of lines 101 thanbefore.

The central office 103 may include a modem termination system (MTS) 104,such as a cable modem termination system (CMTS) for Cable Modem andDSLAM for DSL, which may be a computing device configured to managecommunications between devices on the network of lines 101 and backenddevices such as servers 105-107 that transmit network traffic downstreamto various homes 102 and receive upstream network traffic from varioushomes 102 (to be discussed further below). The MTS may be as specifiedin a standard, such as, in an HFC type network, the Data Over CableService Interface Specification (DOCSIS) standard, published by CableTelevision Laboratories, Inc. (a.k.a. CableLabs), or it may be a similaror modified device instead. The MTS may be configured to place data onone or more downstream frequencies to be received by modems at thevarious homes 102, and to receive upstream communications from thosemodems on one or more upstream frequencies. The central office 103 mayalso include one or more network interfaces 108, which can permit thecentral office 103 to communicate with various other external networks109. In certain embodiments, a central office 103 need not be used, andthe various homes 102 may communicate with the external networks 109directly or via one or more network devices (e.g., routers). Thesenetworks 109 may include, for example, networks of internet protocoldevices, telephone networks, cellular telephone networks, fiber opticnetworks, local wireless networks (e.g., WiMAX), satellite networks, andany other desired network, and the interface 108 may include thecorresponding circuitry needed to communicate on the network 109, and toother devices on the network such as a cellular telephone network andits corresponding cell phones.

As noted above, the central office 103 may include a variety of servers105-107 that may be configured to perform various functions. Forexample, the central office 103 may include a push notification server105. The push notification server 105 may generate push notifications todeliver data and/or commands to the various homes 102 in the network (ormore specifically, to the devices in the homes 102 that are configuredto detect such notifications). The central office 103 may also include acontent server 106. The content server 106 may be one or more computingdevices that are configured to provide content to users in the homes.This content may be, for example, video on demand movies, televisionprograms, songs, text listings, etc. The content server 106 may includesoftware to validate user identities and entitlements, locate andretrieve requested content, encrypt the content, and initiate delivery(e.g., streaming) of the content to the requesting user and/or device.

The central office 103 may also include one or more application servers107. An application server 107 may be a computing device configured tooffer any desired service, and may run various languages and operatingsystems (e.g., servlets and JSP pages running on Tomcat/MySQL, OSX, BSD,Ubuntu, Redhat, HTMLS, JavaScript, AJAX and COMET). For example, anapplication server may be responsible for collecting television programlistings information and generating a data download for electronicprogram guide listings. Another application server may be responsiblefor monitoring user viewing habits and collecting that information foruse in selecting advertisements. Another application server may beresponsible for formatting and inserting advertisements in a videostream being transmitted to the homes 102. Another application servermay be responsible for receiving user remote control commands, andprocessing them to provide an intelligent remote control experience.

An example home 102 a may include an interface, such as a modem 110,which may include transmitters and receivers used to communicate on thelines 101 and with the central office 103. The modem 110 may be, forexample, a coaxial cable modem (for coaxial cable lines 101), a fiberinterface node (for fiber optic lines 101), or any other desired modemdevice. The modem 110 may be connected to, or be a part of, a gatewayinterface device 111. The gateway interface device 111 may be acomputing device that communicates with the modem 110 to allow one ormore other devices in the home to communicate with the central office103 and other devices beyond the central office. The gateway 111 may bea set-top box (STB), digital video recorder (DVR), computer server, orany other desired computing device. The gateway 111 may also include(not shown) local network interfaces to provide communication signals todevices in the home, such as televisions 112, additional set-top boxes(STBs) 113, personal computers 114, laptop computers 115, wirelessdevices 116 (wireless laptops and netbooks, mobile phones, mobiletelevisions, personal digital assistants (PDA), etc.), a VoIP AnalogTelephone Adapter (ATA), and any other desired devices. Examples of thelocal network interfaces include Multimedia Over Coax Alliance (MoCA)interfaces, Ethernet interfaces, universal serial bus (USB) interfaces,wireless interfaces (e.g., IEEE 802.11), Bluetooth interfaces, andothers.

FIG. 2 is another illustration of an example information distributionnetwork 100, including certain additional components on which many ofthe various features described herein may be implemented. As shown inFIG. 2, a user location 102 (e.g., a user's home, office, business,etc.) may be connected to a central office 103 and/or to an externalnetwork 109 via a plurality of intermediary network devices. In thisexample, the network path 101 between the user location 102 and centraloffice 103 includes a downstream network node 220 (which may or may notbe located at user location 102), access router 225, and upstreamnetwork node 230. Aspects of the present disclosure relate to networkmonitoring based on the comparison of network data at the downstreamnetwork node 220 and the upstream network node 230. As described indetail below, such comparisons may allow a network operator to identifyvarious application flows of network traffic between a specific deviceand/or application at a user's location and an external networklocation. An “application flow” refers to the network traffic along anetwork path that is associated with a specific device, application,and/or connection.

As discussed above, the network traffic traveling to and from a userlocation 102 along communication lines 101 may include network trafficfrom many different devices (e.g., devices 112-116). Further, eachdevice 112-116 may simultaneously execute multiple different softwareapplications that transmit or receive data over the network path 101,and each application may initiate multiple different connections toperform the various tasks of the application. Thus, for example, thenetwork traffic passing through the downstream network node 220 andupstream network node 230 in FIG. 2 may include data packets from anonline gaming application executing on a gaming console, data packets ofinternet protocol traffic sent between a browser application executingon a home computer 114 and a remote web server, data packets ofstreaming video sent from a content server 106 to a user's set-top box113 or display device, and so on. The subset of data packets from eachof these applications may comprise a separate application flow. Incertain embodiments, each data packet passing through the downstreamnetwork node 220 and the upstream network node may be associated with asingle application flow only. However, in other embodiments, individualdata packets and groups of data packets may be associated with multipledifferent flows. For example, a data packet originating from ApplicationX running on personal computer 114 may be associated with a firstapplication flow, a second application flow may be associated withApplication Y running on personal computer 114, a third application flowmay be associated with a VOIP call running on an ATA device in theuser's home 102 a, and so on.

A network congestion analyzer 210 may be configured within the network100 to receive network data from the downstream network node 220 andupstream network node 230, and use the information to identify and/orreconstruct different application flows of network traffic and performthe network monitoring and network congestion analysis tasks. Thefunctionality and various aspects of the network congestion analyzer 210and the network nodes 220 and 230 will be described in detail below.Additionally, an external time source 240 may be installed andconfigured on the network 100 to provide a common time signal to thedownstream network node 220 and upstream network node 230. As describedbelow, the common time signal may provide the network nodes 220 and 230with the ability to record reception times or transmission timesassociated with specific data packets, thereby allowing the networkcongestion analyzer 210 to compare the timestamps of data packets whendetermining packet delay, packet delay variance (or jitter), and othernetwork statistics.

In FIG. 2, the network congestion analyzer 210 and the external timesource 240 are shown on a separate network path from the primarycommunication line 101 between the user's location 102 and the centraloffice 103 and/or external network 109. However, either or both of thenetwork congestion analyzer 210 and the external time source 240 may beinstalled on the same communication line 101. For example, the networkcongestion analyzer 210 may be implemented as a network monitoringapplication executing at the user's home 102, the access router 225, orthe central office 103, etc. In other examples, either or both of thenetwork congestion analyzer 210 and the external time source 240 may belocated on a remote network and may communicate with the network nodes220 and 230 via a separate communication network, for example, aseparate fiber optic or coax cable network, or a satellite, telephone,or cellular wireless network, etc.

As shown in FIG. 2, the downstream network node 220 may be located atthe user's location 102. That is, the downstream network node 220 may beimplemented as a separate hardware device installed at the customer'spremises 102, in addition to the devices 110-116 shown in FIG. 1. Inother examples, the downstream network node 220 may be implemented asadditional hardware and/or software integrated within an existingdevice, such as the gateway 111 and/or modem 110 installed at the user'shome 102. For instance, a conventional gateway device 111 or combinationgateway-modem device 110-111 may be provided with additional hardwareand/or software components to support the functionality of a downstreamnetwork node 220 as described herein.

In certain embodiments, it may be advantageous to position thedownstream network node 220 downstream of the gateway 111/modem 110(e.g., between the computing devices 112-116 and the gateway 111/modem110). For instance, the gateway 111 may be a network address translation(NAT) device which converts the private IP addresses used at the user'slocation 102 to the public IP addresses used outside the user's location102. Therefore, by positioning the downstream network node 220 betweenthe gateway 111 and the user's devices 112-116, it may be potentiallyeasier for the downstream network node 220 to identify the devices112-116 and the applications that are associated with certain datapackets.

Additionally, as described above, the user's modem 110 (or anotherinterface device) may be configured to implement a bandwidth restrictionon the user's location 102. For example, a user may purchase apredetermined amount of upstream and downstream bandwidth (e.g., 6 Mbpsdownstream, 2 Mbps upstream) from the network provider, and the modem110 may enforce that bandwidth restriction by limiting the amount datatransmitted between the user's home 102 and the communication network100, for instance, by dropping or delaying any excess upstream ordownstream traffic. Therefore, by positioning the downstream networknode 220 downstream of the modem 110, the downstream network node 220may be able to identify and measure the amount of network trafficflowing to and from the user's devices 112-116 more accurately than adownstream network node 220 positioned upstream of the modem 110. Thus,if the downstream network node 220 is implemented as a separate device,it may be advantageous to position the device downstream of the gateway111 and/or modem 110. Alternatively, if the downstream network node 220is implemented as additional hardware and/or software componentsintegrated within the gateway 111 and/or modem 110, then it may beadvantageous to position these components within the device so thatnetwork node functionality is performed downstream of the gateway andmodem functionality.

In certain embodiments, the functionality of the upstream network node230 may be similar to the functionality of the downstream network node220, in that both network nodes may be configured to store and transmitsimilar sets of network data to the network congestion analyzer 210.Therefore, the hardware/software used to implement the upstream networknode 230 may be similar to the hardware/software used to the implementthe downstream network node 220. However, as shown in FIG. 2, theupstream network node 230 may be positioned at or upstream from anaccess router 225 that is connected to multiple different users homes102. Therefore, additional hardware and software components may be usedfor the upstream network node 230 to support compiling, storing, andtransmitting network data associated with many different user homes 102,and/or filtering the network data based on a user's public IP address.

As shown in FIG. 2, the upstream network node 230 may be installedbetween the access router 225 and the central office 103 and/or externalnetwork 109. The upstream network node 230, like the downstream networknode 220, may be implemented as a separate network device withspecialized hardware and components to perform the network nodefunctionality described herein. In other examples, the upstream networknode 230 may be integrated into an existing network device, such as theaccess router 225 or the central office 103, as additional hardwareand/or software components that are configured to compile informationbased on the network traffic passing through the device and transmit theinformation to the network congestion analyzer 210.

Although this example shows only a single downstream network node 220and a single upstream network node 230, additional network nodes andadditional techniques for positioning and configuring the network nodemay be used in other examples. For instance, a downstream network node220 may be positioned either downstream or upstream from the gateway111/modem 110 at a user's home 102, and one or more additionaldownstream network nodes 220 may be positioned downstream, upstream,and/or in between the gateway 111 and modem 110, in order to capture amore complete picture of the user's network traffic. Additionally,although a single upstream network node 230 may be positioned at or nearan access router 225, other multiple upstream network nodes 230 may bepositioned at other network devices (e.g., other access routers, thecentral office 103), and additional network nodes may be installed asseparate devices at various other points within the communicationnetwork 100.

FIG. 3 illustrates general hardware elements that can be used toimplement any of the various components/computing devices discussedabove. The computing device 300 may include one or more processors 301,which may execute instructions of a computer program to perform any ofthe features described herein. The instructions may be stored in anytype of computer-readable medium or memory, to configure the operationof the processor 301. For example, instructions may be stored in aread-only memory (ROM) 302, random access memory (RAM) 303, removablemedia 304, such as a Universal Serial Bus (USB) drive, compact disk (CD)or digital versatile disk (DVD), floppy disk drive, or any other desiredelectronic storage medium. Instructions may also be stored in anattached (or internal) hard drive 305. The computing device 300 mayinclude one or more output devices, such as a display 306 (or anexternal television), and may include one or more output devicecontrollers 307, such as a video processor. There may also be one ormore user input devices 308, such as a remote control, keyboard, mouse,touch screen, microphone, etc. The computing device 300 may also includeone or more network interfaces, such as input/output circuits 309 (suchas a network card) to communicate with an external network 310. Thenetwork interface may be a wired interface, wireless interface, or acombination of the two. In some embodiments, the interface 309 mayinclude a modem (e.g., a cable modem), and network 310 may include thecommunication lines 101 discussed above, the external network 109, anin-home network, a provider's wireless, coaxial, fiber, or hybridfiber/coaxial distribution system (e.g., a DOCSIS network), or any otherdesired network.

FIG. 4A illustrates a general example of network monitoring and networkcongestion analysis techniques performed on a communication/contentdistribution network 100. The illustrative steps shown in FIG. 4A maycorrespond to the functional steps performed by a network congestionanalyzer 210 in communication with multiple network nodes 220 and 230 ina content distribution network 100.

At step 410, a data capture process is initiated at one or more networknodes in a network 100. For example, referring to the example network100 shown in FIGS. 1 and 2, the data capture may be initiated by thenetwork congestion analyzer 210 via a signal transmitted to thedownstream network node 220 and/or upstream network node 230. Thesignals transmitted to the network nodes 220 and/or 230 may comprisecontrol instructions, for example, HTTP messages, to instruct thenetwork nodes 220 and 230 to begin “capturing” the data traffic thatpasses through the nodes. In other examples, a signal from the networkcongestion analyzer 210 to the network nodes 220 and 230 may betransmitted over a different network path or different network, forexample, a separate fiber optic or coax cable network, or a satellite,telephone, or cellular wireless network, etc. One or more of thesetechniques may be used by the network congestion analyzer 210 toinstruct the network nodes 220 and 230 to begin and end a data captureprocess. In certain examples, the network congestion analyzer may sendcontrol instructions to the network nodes 220 and 230 at or near thesame time, so that the data captured by the nodes is more likely tocontain the same data packets from the same application flows.Additionally, in certain examples, an instruction from a networkcongestion analyzer 210 to a network node 220 or 230 to begin a datacapture process may include a time signal so that the network nodes maysynchronize their data capture activities. However, in other examples,the upstream network node 230 and downstream network node 220 maycommunicate directly with an external time source 240 (as shown in FIG.2), rather than receiving a time signal from the congestion analyzer210.

In other examples, the data capture in step 410 need not be initiated byan instruction sent from the network congestion analyzer 210. Forinstance, the network nodes 220 and 230 may be configured in an “alwayson” mode so that they are constantly capturing (e.g., copying andstoring) data packets passing through the nodes. In this example, thenetwork nodes 220 and 230 may be configured to periodically discardolder network data that has not been requested by the network congestionanalyzer 210 or any other network component. The network nodes 220 and230 may also be configured to begin a data capture process according toa predetermined network monitoring schedule. For instance, an automatedtask may be implemented at each network node 220 and 230 and/or at thenetwork congestion analyzer 210, according to which the network nodes220 and 230 monitor and capture data from the network regularly (e.g., 5minutes every hour) as part of an ongoing network monitoring andcongestion analysis service offered to a user 102.

As described in greater detail below, when data capture is initiated instep 410, the network nodes 220 and 230 may begin a process of capturing(e.g., observing, copying, storing, and/or analyzing) certain networktraffic passing through the node. Therefore, the data captured at anetwork node 220 or 230 may depend on the location of the network nodewithin the network 100. For example, a downstream node 220 installed ata user's home 102 might only be able to capture the network traffictransmitted to and from the user's home 102, while an upstream node 230at an access router 225 or other network device may potentially capturenetwork traffic transmitted to and from multiple different user homes102. Therefore, if a network operator only wants to monitor and analyzethe network traffic of a specific user or customer, then the networkcongestion analyzer 210 may transmit a control instruction to anupstream network node 230 including a parameter that identifies thespecific user location 102 to be monitored, thereby allowing to upstreamnetwork node 230 to control the data capture process (e.g., by filteringdata packets based on the public IP address of the modem 110 at theuser's location 102) to capture only the network traffic associated withthe specific user.

In step 420, the network congestion analyzer 210 receives network datafrom the downstream network node 220, and in step 430, the networkcongestion analyzer 210 receives network data from the upstream networknode 230. As discussed above, the network data received in steps 420 and430 may form the basis for the network monitoring and congestionanalysis activities performed by the network congestion analyzer 210 insteps 440 and 450. Thus, it should be understood that steps 420 and 430need not occur in the order shown in FIG. 2. For example, the networkcongestion analyzer 210 may receive network data in a single largertransmission from each network nodes 220 and 230, or as multipleperiodic transmissions from the nodes.

The network nodes 220 and 230 may transmit the network data to thecongestion analyzer 210 according to a predetermined transmissionschedule (e.g., every five minutes, every hour, etc.), or in response toa control instruction, for example, a transmit data HTTP controlinstruction sent by the congestion analyzer 210 to each network node. Inother examples, the network nodes 220 and 230 may transmit the networkdata based on a previous control instruction. For instance, if thenetwork congestion analyzer 210 previously sent a control instruction tothe nodes 420 and 430 instructing the nodes to capture network data overa five minute period (in step 410), then the nodes 220 and 230 may beconfigured to automatically transmit the captured network data to thecongestion analyzer 210 at the end of the five minute period (steps 420and 430). In other examples, the network congestion analyzer 210 may useseparate control instructions to control the specific activities of thenetwork nodes 220 and 230. For instance, the network nodes may receiveand execute separate control instructions to begin capturing networkdata, stop capturing network data, report status, filter the captureddata (e.g., based on a destination or source address), compress thecaptured data, and transmit the data to the network congestion analyzer210.

As discussed above, application flows may be identified or otherwisereconstructed based on the network data received from the network nodes,and identifying/comparing individual data packets received from onenetwork node (e.g., downstream node 220) with the corresponding datapacket from another network node (e.g., upstream network node 230).Thus, in certain embodiments, the network data received in steps 420 and430 may include complete or partial copies of the data packets that havepassed through a network node during a time window. The data packets maybe in a compressed format to facilitate transmission to the networkcongestion analyzer 210. However, in other examples, the networkcongestion analyzer 210 might not need complete copies of the datapackets for the identification and comparison in steps 440 and 450.Therefore, the network data received in steps 420 and 430 might notinclude complete copies of data packets, but may contain a subset of thepacket information sufficient to allow the network congestion analyzer210 to identify and match specific data packets and assign the packetsinto application flows, for example, source and destination addressesand port numbers, sequence numbers (e.g., for TCP and RTP packets),packet size, and other header and payload data.

The network data received from a downstream network node 220 may bedifferent from the network data received from an upstream network node230. Because the upstream network node 230 may be located, for example,at an access router 225, the network data received from the upstreamnode 230 may include network traffic to and from the user 102 as well asnetwork traffic to and from other users. Thus, in some embodiments,before performing the comparing and analysis in steps 440 and 450, thenetwork data may be filtered at one or more of the network nodes 220 and230, or at the network congestion analyzer 210, so that only networkdata associated with a particular user location 102 is analyzed in step450.

In step 440, the network congestion analyzer 210 identifies and comparesthe data packet information received from the downstream network node220 with the data packet information received from the downstreamnetwork node 230. The techniques used to identify, compare, and/or matchdata packets from the different network nodes may vary depending on thetype of the data packets received. FIGS. 4B and 4C, described below,illustrate two example techniques for identifying and comparingTransmission Control Protocol (TCP) or Real-time Transport Protocol(RTP) data packets (FIG. 4B), and User Datagram Protocol (UDP) datapackets (FIG. 4C). In these examples and others involving differentnetwork protocols or data packet types, the data packets received at onenetwork node (e.g., downstream network node 220) may be matched tocorresponding data packets received at other network node (e.g.,upstream network node 230), based on the matching characteristics orproperties of the data packets. In certain examples, the matchingprocess may involve creating (e.g., virtually) one or more data packettables, or other suitable real or virtual data structures, populatedwith the properties of the data packets received from one or morenetwork nodes. Table 1, an example data packet table, is shown below toillustrate certain data packet properties that may be stored andcompared.

TABLE 1 Sample Data Packet Information Table Packet Node Source SourceDest. Dest. Seq. Hash Time Protocol ID ID Addr. Port Addr. Port Num.Sig. Size Received — — — — — — — — — — —

In this example, when processing received data packets, the networkcongestion analyzer 210 may add a new row to Table 1 for each new datapacket received from either of the network nodes 220 or 230. The networkcongestion analyzer 210 may first assign a unique identifier (Packet ID)to the received data packet, and record from which network node thepacket was received (Node ID). The network congestion analyzer 210 maythen parse and record several identifying fields of the data packet, forexample, the source IP address of the data packet (Source Addr.), thesource port (Source Port), the destination IP address of the packet(Dest. Addr.), the destination port (Dest. Port), the sequence number ofthe packet (Seq. Num) (if applicable), the hash signature of the packet(if applicable), and the packet size (Size). Additionally, although thedata packets themselves might not include any time data, the networknodes 220 and 230 may use the external time source 240 (or other timesource) to determine a timestamp associated with each data packet andmay include the timestamp in the data packet information transmitted insteps 420 and 430. In this example, the network congestion analyzer 210may parse out and include this timestamp data (Time Received) in Table1.

As described above, Table 1 may include data packets received from boththe downstream network node 220 and the upstream network node 230, mayinclude both upstream and downstream network traffic, and may includenetwork traffic from all of a user's devices 112-116 and all of thevarious applications and connections established by those devices.However, in other examples, the network congestion analyzer 210 maycreate different tables (or other data structures) to store differenttypes of data packets and associated information. Separate tables may becreated for the data packets received from different network nodes, forupstream and downstream traffic, for different source or destinationaddresses and ports, and/or for different protocols or packet types,etc. As an example, two tables may be created for each application, anupstream and a downstream table. Thus, for a particular Application X,there may be four total tables: two captured by node 220 and twocaptured by node 230. Therefore, if a network operator is interested inupstream congestion for Application X, he/she may take the upstreamtable of Application X from node 220 and compare packet by packet to theupstream table captured by node 230. Based on this comparison, thepacket loss, latency and other network characteristics may be measured.The list of data fields in Table 1 is merely illustrative, and varioussubsets of these data fields and/or additional data fields describingthe packets may be used in other examples.

Referring now to FIGS. 4B and 4C, sample processes are shown foridentifying and comparing TCP or RTP data packets (FIG. 4B) and UDPpackets (FIG. 4C), received from the network nodes. These sampleprocesses in FIGS. 4B-4C may correspond to step 440 in FIG. 4A. In theseexamples, the sample processes may be performed at the networkcongestion analyzer 210 by retrieving and processing the data packetinformation received from the network nodes 220 and 230. In certainexamples, the network congestion analyzer 210 may first receive andstore the data packet information from the network nodes into a datastructure (e.g., Table 1) before performing the processes in FIGS. 4B-4Cto identify and compare the data packets. Thus, the sample processesshown in FIGS. 4B-4C may begin by retrieving data from a pre-existingpopulated data structure at the network congestion analyzer 210 (e.g.,Table 1, or a combination of other tables and/or alternative datastructures). In other examples, the sample processes shown in FIGS.4B-4C may receive and process the data packet information in real time,for instance, by receiving the data packet information directly from thenetwork nodes 220 and 230.

Referring now to FIG. 4B, the sample process begins in step 441 b byretrieving a data packet from the set of data packets received from afirst network node. For example, step 441 b may comprise accessing anordered data structure (e.g., Table 1) stored at the network congestionanalyzer 210 and retrieving a row corresponding to a data packetreceived from the downstream network 220.

In step 442 b, the network congestion analyzer 210 determines whether ornot the retrieved data packet is a TCP or RTP packet, for example, byreviewing a Protocol field in a data packet table (e.g., Table 1), oraccessing a protocol header or the payload data within the data packetitself. If the packet is not a TCP or RTP packet (Step 442 b:No), thenthe sample process in FIG. 4B is not the appropriate process for thedata packet, and the process returns to step 441 b to await theretrieval of another data packet. However, if the data packet isidentified as a TCP or RTP packet (Step 442 b:Yes), then the process mayproceed to step 443 b to identify one or more application flowscorresponding to the data packet. As discussed above, an applicationflow is a set of data packets transmitted over a network path 101 thatmay be associated with specific network traffic, software applicationsand/or connections at a specific device 112-116 at a user location 102.

In step 443 b, the network congestion analyzer 210 may retrieve certainproperties from the data packet, such as the source IP address, sourceport, destination IP address, destination port, and IP protocol number(e.g., UDP, TCP), in order to determine the application flow(s) thatinclude the data packet. In certain embodiments, the network congestionanalyzer 210 may access a reference table listing commonly used portnumbers, IP addresses, and protocols, etc., along with associated deviceand application identifiers, to allow the network congestion analyzer210 to identify the application flow of a data packet. For example, ifthe network congestion analyzer 210 retrieves a data packet transmittedfrom port 1719, it may determine by accessing a port/application tablethat a certain voice-over-IP (VOIP) application uses ports 1719 and 1720for its network traffic.

As discussed above, a downstream network node 220 may be installeddownstream of a network address translation (NAT) device (e.g., gateway111) installed at the user's location 102, so that the IP address of theuser's device 112-116 will be a private IP address that identifies thedevice itself. In other examples, if the downstream network node 220 isinstalled upstream of a NAT device, then the IP address of the devicerecorded in the data packet may be a translated public IP address thatidentifies the user's modem 110 or gateway 111.

Also in step 443 b, the network congestion analyzer 210 may identifymultiple data packets as part or members of the same application flow.For example, after determining an application flow of a first datapacket, the network congestion analyzer 210 may assign an applicationflow identifier to the data packet and/or may store the data packet in aseparate table dedicated to the application flow. Additionally, thenetwork congestion analyzer 210 may identify the correct applicationflow for subsequent data packets by matching certain properties withother data packets that have been previously analyzed and assigned to anapplication flow.

After determining the application flow of the data packet in step 443 b,the TCP or RTP sequence number of the data packet is identified is step444 b. Using the sequence number of the data packet, the networkcongestion analyzer 210 may then organize the data packets of theapplication flow according to their sequence numbers to facilitate thepacket matching and analyses performed in subsequent steps.

In step 445 b, the network congestion analyzer 210 matches the datapacket from the first network node (e.g., the downstream network node220) with a corresponding data packet from the second network node(e.g., the upstream network node 230). As discussed above, matching datapackets may be identified by certain similar properties, such as thesame source and/or destination address, the same source and/ordestination port, and the same sequence number. However, there areinstances when these properties might not always match in thecorresponding data packets from different network nodes. For instance,if the network nodes are positioned on opposite sides of a NAT device orother network component that alters or repackages network traffic, thena subset of these data packet properties and/or additional propertiesmay be used to match the data packets. Additional techniques that may beused to match the data packets between different network nodes mayinclude, for example, matching the payload size, payload hashingtechniques, and matching data packets that have approximately (althoughnot exactly) the same timestamp at the different network nodes. Table 2,shown below, is a sample downstream network traffic table containing twomatching data packets from a downstream network node 220 and an upstreamnetwork node 230.

TABLE 2 Sample Matching TCP Data Packets Packet Node Source Source Dest.Dest. Seq. Time Protocol ID ID Addr. Port Addr. Port Num. Size ReceivedTCP 123 220 1.2.3.4 80 5.6.7.8 80 18 220 B 01:35:07.478 — — — — — — — —— — TCP 456 230 1.2.3.4 80 5.6.7.8 80 18 220 B 01:35:08.056

In step 446 b, the network congestion analyzer 210 compares thetimestamps of matching data packets from the downstream and upstreamnetwork nodes 220 and 230 in order to perform network analysis tasks,such as determinations of packet loss, packet delay, and packet delayvariation (or jitter). As mentioned above, the downstream and upstreamnetwork nodes 220 and 230 may be synchronized, for example, by receivinga common time signal from an external time source 240. Thus, thedifference in timestamps in matching data packets may represent thenetwork path transmission time between the network nodes 220 and 230with a high degree of accuracy.

In sample Table 2, the matching data packets 123 and 456 have atimestamp difference of +0.578 seconds, indicating that this data packetis being transmitted upstream (e.g., from a user's device 112-116 to thecentral office 103 or external network 109), and has a packet delay of0.578 seconds. In other examples, if a matching data packet is not foundin step 445 b, the network congestion analyzer 210 may conclude that thedata packet was dropped in between the network nodes 220 and 230.Accordingly, in step 446 b, the network congestion analyzer 210 mayincrement a packet loss counter to reflect the dropped packet in thisapplication flow. Additionally, packet delay variation, or jitter,refers to differences in packet delay between data packets in the sameflow. Packet delay variation may result in packets being received out oforder at or one both of the network nodes 220 and 230. Packet jitter maybe detected by identifying out of order sequence numbers in the receivedpackets, or by comparing the packet delay (e.g., the difference intimestamps) of multiple different packets in the same flow. After asignificant number of data packets from an application flow have beenreceived and analyzed, the network congestion analyzer 210 may use anyof several well-known statistical techniques (e.g., variance) tocalculate the packet jitter for the application flow.

Referring now to FIG. 4C, a sample process is shown similar to theprocess shown in FIG. 4B. However, the process shown in FIG. 4C isconfigured to retrieve and analyze UDP data packets, rather than TCP andRTP packets as discussed above. Although several steps of theseprocesses are similar, UDP packets do not include sequence numbers orany other information to allow the network congestion analyzer 210 todetermine the packet sequence. Accordingly, the sample process of FIG.4C includes a hashing step (445 c) to generate a unique packetidentifier that may be matched with the data packets from other networknodes.

In step 441 c, as in the previous example, the process executing on thenetwork congestion analyzer 210 retrieves a data packet from the set ofdata packets received from the downstream network node 220. In step 442c, the network congestion analyzer 210 determines whether or not theretrieved data packet is a UDP packet, for example, by reviewing aProtocol field in a data packet table (e.g., Table 1), or accessing aprotocol header or payload data within the data packet itself todetermine the network protocol of the packet. If the packet is not a UDPpacket (Step 442 c:No), then the sample process in FIG. 4C is not theappropriate process for the data packet, and the process returns to step441 c to await another the retrieval of another data packet. However, ifthe data packet is identified as a UDP packet (Step 442 c:Yes), then theprocess may proceed to step 443 c to identify one or more applicationflows corresponding to the UDP data packet using techniques similar tothose discussed above in reference to step 443 b.

In step 444 c, the network congestion analyzer 210 may sort the datapackets in the UDP application flow based on the timestamp associatedwith the data packets. As mentioned above, UDP data packets do notinclude a sequence number. Therefore, sorting data packets based ontheir timestamps (e.g., the times the network packets were received atthe downstream network node 220) may be used a preferred approximationof packet sequence in this example. However, other sorting methods basedon other data packet properties may be used. Additionally, in certainexamples, the sorting step 444 c need not be performed, for instance, ifthe packets are captured in sequence order.

In step 445 c, the network congestion analyzer 210 performs a hashfunction (e.g., an MD5-Hash excluding the UDP source port and source IPaddress) on the data packet received from the downstream network node220, and generates a hash signature for the data packet. Thus, in thisexample, both network nodes 220 and 230 would likely transmit fullcopies of the data packets, including their entire payloads, to thenetwork congestion analyzer 210 to allow for the hashing function.However, in other examples, the hashing function may be performed by thenetwork nodes 220 and 230 before transmission, rather than by thenetwork congestion analyzer 210 after transmission. In these examples,the network nodes 220 and 230 might only transmit hash signatures to thenetwork congestion analyzer 210 rather than transmitting the entirepayload of the data packets. In any case, depending on the hashalgorithm used, the hash signature generated in step 445 c may be uniqueamong other data packets in the application flow with a high degree ofconfidence. These hash signatures may be stored at the networkcongestion analyzer 210 and associated with their respective datapackets, for example, as a data field in Table 1.

In step 446 c, the network congestion analyzer 210 matches the datapacket from the first network node (e.g., the downstream network node220) with a corresponding data packet from the second network node(e.g., the upstream network node 230). In this example, the matching maybe performed by matching a hash signature from a data packet receivedfrom the downstream network node 220 with the same hash signature from adata packet received from the upstream network node 230. Additionally,as discussed above in reference to step 445 b, other data fields anddata packets may be used to match the data packets from differentnetwork nodes, such as the source and destination addresses and ports,packet size, protocols, timestamps, and other header information. Table3, shown below, is a sample table containing two matching UDP datapackets from a downstream network node 220 and an upstream network node230.

TABLE 3 Sample Matching UDP Data Packets Packet Node Source Source Dest.Dest. Hash Protocol ID ID Addr. Port Addr. Port Sig. Size Time ReceivedUDP 222 220 4.3.2.1 443 8.7.6.5 443 a48ef2 865 B 02:57:27.045 — — — — —— — — — — UDP 333 230 4.3.2.1 443 8.7.6.5 443 a48ef2 865 B 02:57:27.002

In step 447 c, the network congestion analyzer 210 compares thetimestamps of matching data packets from the downstream and upstreamnetwork nodes 220 and 230 in order to perform network analysis tasks,such as determinations of packet loss, packet delay, and packet delayvariation (or jitter). In sample Table 3, the matching UDP data packets222 and 333 have a timestamp difference of −0.043 seconds, indicatingthat this data packet is being transmitted downstream (e.g., from thecentral office 103 or external network 109 to a user's device 112-116),and has a packet delay of 0.043 seconds. Step 447 c may also includedeterminations of packet loss, packet delay and packet delay variation(or jitter) of UDP packets and UDP application flows may be performedusing well-known statistical analysis techniques.

Returning now to FIG. 4A, in step 450 the network congestion analyzer210 may perform additional network monitoring and/or a networkcongestion analysis based on the earlier analyses performed in step 440.As discussed above, the congestion analysis may include analyzingdownstream network congestion (using traffic from the upstream networknode 230 as a reference point) and/or analyzing upstream networkcongestion (using traffic from the downstream network node 220 as areference point). Additionally, the different analyses in steps 440 and450 may correspond to different scopes of network traffic. For instance,step 440 may include analyses of individual data packets and individualapplication flows, such as determinations of packet loss andcalculations of packet delay and packet delay variation, while step 450may include one or more analyses of the multiple application flowsand/or multiple devices in a user's location (e.g., customer's home)102. Thus, an analysis in step 450 may compare the amount of upstreamand/or downstream bandwidth being used by the various applications(e.g., VOIP applications, gaming console applications, mobile devices,video streaming applications, televisions, computers, set-top boxes,etc.) at the customer's home 102.

FIG. 5 illustrates a sample graph showing one type of network congestionanalysis that may be performed in step 450. The five-minute time windowshown in this graph indicates that the downstream and upstream networknodes 220 and 230 may have received control instructions to begincapturing data from 10:07 am to 10:12 am. In this example, after thedata capture process, the transmission of data to the network congestionanalyzer 210, and the subsequent analysis, the network congestionanalyzer 210 has generated a chart displaying the bandwidth usage offour different application flows: a primary television 112 in the user'shome 102 receiving television programming from a content server 106; adigital video application downloading movies from the central office 103(e.g., to the user's set-top box 113 or personal computer 114); a gamingconsole application communicating with an external network 109 foronline gaming; and a voice over IP (VOIP) application (e.g., executingon the user's desktop computer 114 or laptop 113). In this example, thegraph shown in FIG. 5 may correspond to the user's downstream networktraffic only, and a separate graph (not shown) may be generated for theuser's upstream traffic. If the user in this example has purchased 6Mbps of downstream network bandwidth, then the graph in FIG. 5 mayindicate that the user is using most or all of its allotted downstreambandwidth and certain of the user's devices 112-116 may be experiencingpacket loss and/or delay. It should be understood that graphs, such asthe example shown in FIG. 5, may be virtual and may take any form withinthe network congestion analyzer 210. Such graphs also may be output toany display device or other output connected to the analyzer 210.

Based on graphs like the example shown in FIG. 5, users or providers maydecide how best to manage their devices and network resources. Forexample, the user may reconfigure certain applications (e.g., moviedownloading for future viewing) to run at non-peak times, or may turnoff certain devices while running certain applications on other devicesthat require a high level of network quality (e.g., a VOIP or videoconference call). In other examples, users may review their bandwidthusage graphs and see that they have additional unused bandwidth atcertain times, and therefore may configure their applications or devices(or install new applications or devices) to use the available bandwidth.In still other examples, users may see from their bandwidth usage graphsthat they have purchased the wrong amount of upstream and/or downstreambandwidth for their preferred devices and applications. Accordingly,some users may decide after reviewing their usage graphs and statisticsthat they need more bandwidth for their preferred devices andapplications, or that they do not need as much bandwidth as they havepurchased, and thus the user may change their bandwidth purchase plan asdesired.

FIG. 6 illustrates another example of a network congestion analysis thatmay be performed in step 450 of FIG. 4. In FIG. 6, a chart is showndisplaying network traffic statistics for a plurality ofdevices/applications operating at a user's home 102. As discussed above,each device 112-116 at a user location 102 may execute one or moreapplications that correspond to application flows. In this example, theApplication field 601 is populated with a device and/or application namethat may be readily identifiable to a user or network operator whenanalyzing the usage data. The Source Port field 602 and Destination Portfield 603 identify the source and destination ports used by thedevice/application to transmit and receive network traffic. The AverageMbps field 604 contains a calculation of the average amount of bandwidth(e.g., either upstream or downstream) used by the application over themeasured time window, and the % Mbps field 605 corresponds to thepercentage of the user's overall bandwidth usage that the applicationrepresents. As in the above example, the chart in FIG. 6 may correspondto a user's downstream network traffic. Also, as shown in the measuredtime window the user may be using all or most of a 6 Mbps purchaseddownstream bandwidth allotment. The sample chart in FIG. 6 also includesan Average Latency field 606 showing the average network pathtransmission time between the downstream network node 220 and theupstream network node 230 for each application. Additionally, FIG. 6includes a Dropped Packets field 607 indicating the number of droppedpackets in the application flow (or applications flows) for theapplication during the measured time window.

Based on the data in FIG. 6 and other related information, users andnetwork operators (e.g., network providers) may be able to determinenetwork usage and measure network quality for various devices andapplications executing in a user's home 102. For example, users maysubmit complaints to a network operator based on network delays orperformance degradations for one or more of the user's devices 112-116and/or applications. In response to the complaint, the network operatormay direct the network congestion analyzer 210 and network nodes 220 and230 to perform a data capture and analysis as described above. Then,using the statistics and analyses shown in FIGS. 5 and 6, the networkoperator or the user may assess the level of network usage for theuser's devices, identify the causes of any network delays or performancedegradations, and may suggest possible solutions to any networkcongestion problems.

FIG. 7 illustrates a general example of a method for receiving datapackets and transmitting data packet information on a network 100. Asdiscussed above, the illustrative steps shown in FIG. 4A were describedas functional steps that may be performed by a network congestionanalyzer 210. However, the data packets may be first received andprocessed by one or more network nodes installed on the communicationlines 101. Additionally, in certain examples, some (or all) of the datapacket processing and network congestion analysis may be performed atthe network nodes. Accordingly, the illustrative steps shown in FIG. 7may correspond to the functional steps performed by one or more networknodes in the network 100, for example the downstream network node 220and upstream network node 230 shown in FIG. 2.

In step 710, the network node (e.g., downstream network node 220 orupstream network node 230) may receive a control instruction to begincapturing data packets transmitted over the communication lines 101. Asdiscussed above in reference to FIGS. 4A-4C, a network congestionanalyzer 210 may send a control instruction (e.g., an HTTP message) tothe network nodes 220 and 230 to command the nodes to begin capturingdata packets. Such an instruction may be based on a user request, forexample, from a network operator or a user interested in monitoring andanalyzing network traffic.

Although this example involves a control instruction, it should beunderstood that additional techniques may be used initiate the datapacket capture process at a network nodes 220 and 230. For example, asdiscussed above, the network nodes 220 and 230 may continuously capturedata packets, or may capture packets according to a predeterminedschedule, etc.

In step 720, the process executing at a network node 220 or 230 enters acontrol loop for a specific time window during which the network nodewill capture data packets as they are transmitted along thecommunication lines 101. In other examples, the data packet captureprocess in FIG. 7 need not be based on a predetermined time window. Forinstance, the data packet capture process may be configured to exitafter capturing a certain number of data packets, or may be configuredto start and stop capturing data packets only in response to controlinstructions received from the network congestion analyzer 210 or othercomponent. Additionally, if a user or network operator is onlyinterested in analyzing a particular aspect of network congestion, thenduring the data packet capture process beginning in step 720 the networknodes 220 and 230 may be configured to capture only certain types ofdata packets. For example, a control instruction received from thenetwork congestion analyzer 210 may include parameters specifying thatonly data packets with the specified protocol(s), source address(es),destination(s), port(s), etc., should be captured by the network node.For instance, if a network operator wishes to analyze a user'sdownstream network traffic and is not interested in the user's upstreamnetwork traffic, then the network nodes 220 and 230 may be configured toonly capture downstream traffic (e.g., data packets having a destinationaddress corresponding to one or the devices in the user's home 102).

Steps 730-750 correspond to steps that may be implemented within thedata packet capture process. In step 730, a network node 220 or 230receives a data packet and determines that the data packet is being sentto or from a device 112-116 in the user's home 102. In step 740, anetwork node 220 or 230 stores information describing the received datapacket, for example, in a local memory at the network node. In someexamples, the network nodes 220 and 230 may copy the entire data packet,while in other examples it may be sufficient for the network nodes tocopy only a subset of the data packet fields and/or payload. Forexample, as discussed below, any header fields or other portions of thedata packet that will not be used to match the data packet with acorresponding packet from a different network node need not be stored atthe local network node in step 740. Additionally, the network nodes 220and 230 may store a timestamp in step 740 associated with each storeddata packet. As discussed above, data packet timestamps may be generatedby the network nodes 220 and 230 to reflect the time the data packetsarrived at the network nodes, using a time signal from an external timesource 240 synchronized with the other network nodes.

In step 750, a network node 220 or 230 transmits the data packet in itsoriginal form over the communication pathway 101 to its intendedrecipient. Thus, even though the data packets received by the networknodes 220 and 230 during the capture process may be read, parsed,copied, and/or stored, these steps need not affect the delivery of theoriginal unaltered packets to their intended recipients. In someinstances, network delays may occur as a result of the additional tasksperformed in steps 730 and 740, therefore, it may be advantageous tominimize the amount of processing required until after the data packethas been transmitted in step 750. For instance, the processing taskssuch as searching the data packets for specific fields and/or criteria,parsing out certain data fields, and compressing the data packets, maybe postponed until after step 750 for performance reasons in certainembodiments.

In step 760, at the end of the data capture time window, the datacapturing process executing at the network node 220 or 230 terminatesand the network node ceases capturing data packets. As discussed above,in other examples, step 760 might not correspond to the end of a timewindow, but may instead correspond to the end of a predetermined numberof packets to be captured, or to another control instruction received bythe network node 220 or 230 instructing the node to stop the data packetcapturing process.

In step 770, the network node 220 or 230 transmits the data packetinformation collected in the previous steps to the network congestionanalyzer 210. As discussed above, this data packet information mayinclude complete copies of each of the data packets received at thenetwork node during the time window and a timestamp associated with eachpacket. Alternatively, the data packet information may include only asubset of the data fields, for example, by removing any extraneous datafields that will not be used by the network congestion analyzer 210. Forinstance, in certain embodiments, the network congestion analyzer 210might not use the packet payload at all when matching, comparing, andanalyzing the data packets and application flows. In this example, thenetwork nodes 220 and 230 may strip out the payload information prior totransmission. Any data packet header fields that are not used for thematching and comparing processes described in FIGS. 4A-4C might also bestripped out from the data packet information before transmitting instep 770. Additionally, the network nodes 220 and 230 may employ any ofseveral well-known data compression techniques to further compress thedata packet information before transmission. Finally, the data packetinformation and timestamp data are transmitted to the network congestionanalyzer 210, so the congestion analyzer can perform the data packetidentification, matching, and application flow congestion analysisdescribed above in reference to steps 440-450.

Aspects of the disclosure have been described in terms of illustrativeembodiments thereof. While illustrative systems and methods as describedherein embodying various aspects of the present disclosure are shown, itwill be understood by those skilled in the art, that the disclosure isnot limited to these embodiments. Modifications may be made by thoseskilled in the art, particularly in light of the foregoing teachings.For example, each of the features of the aforementioned illustrativeexamples may be utilized alone or in combination or subcombination withelements of the other examples. For example, any of the above describedsystems and methods or parts thereof may be combined with the othermethods and systems or parts thereof described above. For example, oneof ordinary skill in the art will appreciate that the steps illustratedin the illustrative figures may be performed in other than the recitedorder, and that one or more steps illustrated may be optional inaccordance with aspects of the disclosure. It will also be appreciatedand understood that modifications may be made without departing from thetrue spirit and scope of the present disclosure. The description is thusto be regarded as illustrative instead of restrictive on the presentdisclosure.

What is claimed is:
 1. A method, comprising: comparing, by a computingdevice, first identifying information relating to a first data packetassociated with a first network element to second identifyinginformation relating to a second data packet associated with a secondnetwork element; determining, by the computing device, based on thecomparison, that the first data packet and the second data packetcorrespond to the same data packet at different locations in a networkpath comprising at least the first network element and the secondnetwork element; and performing, by the computing device, an analysis ofthe network path.
 2. The method of claim 1, wherein the firstidentifying information comprises a first timestamp and the secondidentifying information comprises a second timestamp, and whereinperforming the analysis of the network path comprises comparing thefirst timestamp and the second timestamp.
 3. The method of claim 1,wherein the first identifying information corresponds to the first datapacket collected downstream of an access modem, and the secondidentifying information corresponds to the second data packet collectedupstream of the access modem.
 4. The method of claim 1, wherein thefirst data packet and the second data packet are Transmission ControlProtocol (TCP) packets or Real-time Transport Protocol (RTP) packets,and wherein determining that the first data packet and the second datapacket correspond to the same data packet comprises comparing a packetsequence number from the first identifying information to a packetsequence number from the second identifying information.
 5. The methodof claim 1, wherein the first data packet and the second data packet areUser Datagram Protocol (UDP) packets, and wherein determining that thefirst data packet and the second data packet correspond to the same datapacket comprises: determining a first hash signature associated with apayload of the first data packet; determining a second hash signatureassociated with a payload of the second data packet; and comparing thefirst hash signature and the second hash signature.
 6. The method ofclaim 1, wherein performing the analysis of the network path comprises:identifying a plurality of application flows on the network path; anddetermining an amount of network usage for each of the plurality ofapplication flows.
 7. The method of claim 6, wherein performing theanalysis of the network path further comprises calculating at least oneof an amount of packet delay, an amount of packet delay variation, or anumber of dropped packets for each of the plurality of application flowson the network path.
 8. The method of claim 1, further comprising:comparing third identifying information relating to a third data packetassociated with the first network element to fourth identifyinginformation relating to a fourth data packet associated with the secondnetwork element; determining, by the computing device, that the thirddata packet and the fourth data packet correspond to the same datapacket at different locations in the network path; and determining thatthe first and second data packets belong to a first application flow,and determining that the third and fourth data packets belong to asecond different application flow, wherein performing the analysis ofthe network path comprises performing separate data flow analyses forthe first and second application flows.
 9. A method, comprising:receiving, by an intermediary network node, one or more data packetstransmitted by at least one transmitting node; creating, by theintermediary network node, a data set comprising characteristics of theone or more data packets; transmitting, by the intermediary networknode, the one or more data packets to at least one destination node; andtransmitting, by the intermediary network node, the data set to anetwork analyzer.
 10. The method of claim 9, wherein creating the dataset comprising characteristics of the one or more data packetscomprises: receiving a control instruction from the network analyzer tobegin capturing data packets; and storing the one or more data packetstransmitted by the transmitting node, in response to the receiving thecontrol instruction.
 11. The method of claim 9, wherein the received oneor more data packets comprises data packets corresponding to a pluralityof different application flows, each said application flow associatedwith a different transmitting node.
 12. The method of claim 9, furthercomprising: receiving a signal from an external time source; creating atimestamp associated with a first data packet in the one or more datapackets, said timestamp based on the external time source and based on atime that the first data packet was received at the intermediary networknode; and storing the timestamp as a data field within the data set. 13.The method of claim 9, further comprising: determining that a first datapacket in the one or more data packets is one of a Transmission ControlProtocol (TCP) packet or a Real-time Transport Protocol (RTP) packet;identifying a TCP or RTP sequence number associated with the first datapacket; and storing the TCP or RTP sequence number associated with thefirst data packet as a data field within the data set.
 14. The method ofclaim 9, further comprising: determining that a first data packet in theone or more data packets is a User Datagram Protocol (UDP) packet;creating a first hash signature based on the first data packet; andstoring the first hash signature as a data field within the data set.15. A system, comprising: a first network element in a network path; asecond network element in the network path; and a network path analyzerconfigured to: receive first data corresponding to a first data packetfrom the first network element; receive second data corresponding to asecond data packet from the second network element; compare the firstdata and the second data; determine, based on the comparison, that thefirst data packet and the second data packet correspond to the same datapacket at different locations in the network path; and perform ananalysis of the network path, using the first data and the second data.16. The system of claim 15, wherein the first data received from thefirst network element comprises a first timestamp and the second datareceived from the second network element comprises a second timestamp,and wherein performing the analysis of the network path comprisescomparing the first timestamp and the second timestamp.
 17. The systemof claim 15, wherein the first data packet and the second data packetare Transmission Control Protocol (TCP) packets or Real-time TransportProtocol (RTP) packets, and wherein determining that the first datapacket and the second data packet correspond to the same data packetcomprises comparing a packet sequence number from the first data to apacket sequence number from the second data.
 18. The system of claim 15,wherein the first data packet and the second data packet are UserDatagram Protocol (UDP) packets, and wherein determining that the firstdata packet and the second data packet correspond to the same datapacket comprises: determining a first hash signature associated with apayload of the first data packet; determining a second hash signatureassociated with a payload of the second data packet; and comparing thefirst hash signature and the second hash signature.
 19. The system ofclaim 15, wherein performing the analysis of the network path comprises:identifying a plurality of application flows on the network path; anddetermining an amount of network usage for each of the plurality ofapplication flows.
 20. The system of claim 19, wherein performing theanalysis of the network path further comprises calculating at least oneof an amount of packet delay, an amount of packet delay variation, or anumber of dropped packets for each of the plurality of application flowson the network path.